Hi Divakaran,
You can't import an AutoCAD template (.dwt) for use in Fusion drawings. Fusion has two default drawing templates, ASME and ISO, which control settings like dimension style, sheet size, etc. You can create a new drawing template in Fusion, but it will be based one one of these two default templates.
If you have a title block (not entire template) created in AutoCAD you can import the DWG, but we limit the DWG you can import to only Fusion-drawings supported entities, no block references, xrefs, etc. Here's some Help info on importing custom title block DWGs: Inserting custom title blocks .
Thanks,
Chris